Percussion tool



h -Jue 16, 1931. FLL.. o. WADSWORTH PERCUS S ION TOOL Filed Aug. 2, 192i l `2 Sheets-Sheet l mm um. @2M E June-16, 1931. F. L. o. WADSWORTH PERCUSS ION TOOL 2 sheets-sheet 2 Filed Aug. 2, 1921 Patented June 16, 1931 PATENT' oFFicE FRANK LO. WADSWOBATI'I, OF lIITSBURGrI-,i,1?:ElN'NSYLVANAV PERCUSSION TGOL Application filed August 2, 1921. 4Serial No. 489,189.

My invention relates toimprovements in the type ofhammer described in my earlier applicatiomerial No. 369,339, filed March 27, 1920, Patent 1,592,130; and it has to do 5) in part with the method of operation, and in part with the structure. and arrangement of the valve elements of pressure-operated-impact tools of this character.V rlhe particular 4features of improvement which form the subljectqnatterv of this application will appear from the following description of two illustrative embodiments of my invention that are respectively depicted inFigs. 1 to 3 and 4 to 6, inclusive, of the accompanying drawings, in which: Y Y

Figure 1 is a. side elevation-partially in section-of a pneumatic riveting hammer of the long stroke free piston expansionv type; Figs. 2 and 3 are central longitudinal sections (on an enlarged scale) of the handle end of this same construction showing the distribution valve elements in different successive p0- sitions of operations; Fig'. l is another view, similar to Fig. 1, of another exemplication of my improved construction; and Figs. 5 and 6 are enlarged views (similar to Figs. 2 and 3) showing the distribution valve elementsof this second exemplilication in successive control positions. i

of the drawings, the barrel of the hammer comprises an outer tubular member 1, which is provided at its front end 'withra sleeve bearing for the reception of a rivet set 2, and which is threaded at its rear end for the at-V tachment of the handlemember 3. This ,barrel carries an inner tubular member @which receives and guides the reciprocating piston 4.0 element 5; and this inner tube is clamped supported in the front end of the outer tubular member l-and the endrof a cylindrical recess 2'" that isA formed in the hub of the handle 3.v vThe rear end of the hammer sbar-Y rel is bored andinternally threaded to receive a two-part valve box, which consists of a rear sectioniS, that is screwed into the-biarrelf, and a front-secion 9, that engages the outer surface of ythe inner tubular -member e and thus maintains the parts i- 8 and 9 in En the construction shown on the first sheet in place between an annular collar G-that is concentric relation with each other. The

space between the exterior of the inner tube 4L and the interengaged concentric valve box sections 8 and 9 constitutes an annular chamber for the reception and guidance of a twopart distribution valve, which consists'of a front section 12, that is provided witlrtwo flanges 13 and 14, and a rear section 15 that overlaps the front section and is likewise pro`k vided with two other flanges v16 and 17. The front end of the rear section 15 is perforated with an annular row of ports 18-18, that are located back of the flange 16; land the central portion of this section is provided with a wide shallow groove 19, which communicates at its rear edge with one or more vents 20 that pierce the valve shell just behind' the .flange 17. The adjacent portion of the inner tube is provided with two annular rows ofv ports 214-21 and 22-22- which serve respectively as inlet and exhaust ports for the rear endvof the Vpiston chamber and with an intermediate row of vent openings `23, which open intothe groove 19 inl theA rear valve section Another v,rowY ofA smallar ports 24 connect the intermediate partv of the piston chamberv withthe annular chamber 25 in front ofthe valve flange'13; and the collar 6' (which carries the front end of the tube 4) is providedl with av series of radial openings 10 that lead from the front end of the piston chamber into the annular spacefll, between the outer'tube land the acent surfaces of the Vmembers f6 and 9.v rEhe rear valve box section 8vr is provided with a series of longitudinalpassageways 26` thatconnect the conduit 11 with a groove 27 on the inner surface ofthe valve boX; and one or vmore 'of these passages 26 are provided with radial ports 28,that communicate with that portion ofthe chamber 25 in'vwhichV the valve flange 13 reciprocates; The valvevv boX'is also provided with a series of radial passages 29, that open, attheir inner ends,

into `,the vchamber baclr of the valve ange 9 16, and at theirouter yends into an annular groove 30' onthe inner adjacent surface of the outer tube 1;l and the groove 39 com.` municates in turn with the outer air throughL an annular row of ports 31-31. A restricted port 32 leads from the live air reservoir 7, in the hammer handle, to the space back of the rear valve flange 17; and one or more small passages 33 (one of which is shown in full and one in dotted lines in Figs. 2 and 3) lead from this same reservoir 7 to that part of the valve chamberin which the flange 14E reciprocates.

In putting together the parts of the above described construction, the assembled members 4-6-8-9-12 and 15 may be inserted as a unit in the hammer barrel 1; and the rear valve box section 8 is then screwed home until its front end is tightly engaged with the shoulder 34 of the annular recess 30. A compressible washer S35-of soft metal, or fibre, or other suitable material-is slipped over the reduced end portion of the valve box and the handle 3 is screwed onto the exterior of the outer tubular member 1 until the rear end of the inner tube 4land the washer 35 are both engaged by the adjacent faces of the recess in the handle boss. The handle is then locked in place on the barrel by the use of an eccentric headed pin 36 which engages with ratchet teeth on the end of the threaded handle sleeve-(as shown and described more fully in my copending application Serial No. 483,794, liled July 11, 1921)-and the locking device is covered by a split spring ring 37 which is provided on one side with a series of openings 38, and which serves both as a retaining clip for the locking pin 3G and as an exhaust deflector for the waste motive fluid escaping from the ports 31-31.

The operation of the mechanism shown in Figs. 1 to 3, inclusive, is as follows: I/Vhen motive fluid is admitted to the reservoir 7 (through the passage 39 in the hammer handle) the piston 5 will be moved, either forward or back, by the flow of the high pressure air through the co-operating passageways and ports in the valve and valve box members. If, for example, the interengaged valve elements 12 and 15 are in the forward position shown in Fig. 1, the live motive fluid will pass directly through the open ports 21 into the rear end of the piston chamber, and will drive the piston 5 toward the rivet set 2. In this position of the valve elements the valve flange 16 is in' advance of the groove 27 and there is a direct communication between the latter and the radial openings 29; and the air in front of the advancing piston will therefore be allowed to escape freely to the external atmosphere through the communicating ports and passages 10-11-26- 27-29-30-31 and 38. During the first partof the forward movement of the piston mem ber, the small ports 24 are either open to the exhaust or are covered by the piston 5; and the valve elements 12 and 15 are therefore maintained in the position shown in Fig. 1 by the unbalanced pressure of the live motive `fluid which acts directly on the exposed rear end of the valve shell 15 and which is admitted to the chamber back of the valve flange 17 both through the restricted passageway 32, and through the ports and openings 23 19-20. But as soon as the piston, in its forward movement, has passed beyond and uncovered the row of ports 24, the live motive fluid in the rear thereof will enter the chamber 25 and the pressure of this fluid on the valve flange 13, will overcome the pressure on the rear of the flange shell 15 and its flange 17, and the two interengaged valve elements 12 and 15 will loe moved rearwardly to the position shown in Fig. 2.

In this second position of the parts the inlet ports 21 are all closed, but a small amount of live motive fluid continues to flew into the rear end of the piston chamber through the restricted passageways 32-20-19 and 23. The communication between the groove 27 and the exhaust ports 29 is now out off by the valve fiange 16; and a communication between the rear end of the piston chamber and the surrounding chamber 11 is established by the opening of the small port or ports 28, which permits a part of the high pressure fluid to flow through the passageways 2&1- 25-28 and 26 into the now closed reservoir 11 and the communicating space in front of the advancing piston. As the forward movement continues the pressure in the rear of the piston-and on the front of the valve flange 13-is continually reduced by the expansion of the trapped motive fluid in the rear of the piston; while the pressure on the front of the piston-which is substantially the same as that in the reservoir 11 and the space between the valve flanges 14 and 16-is continually increased, partly by the compression of the air in front of the advancing piston and partly by the restricted flow of higher pressure air through the ports 28. But the relative sizes of the auxiliary supply ports, 32-23, and the equalizing ports 28,-and the relative volumes of the piston chamber and the segregation chamber 11-are such that the expansion pressure on the rear end of the piston is always substantially greater than the accumulating pressure on the front end, and the impact member is therefore driven forward at a continually accelerated velocity until it delivers its blow on the rivet set 2 or other operating tool element. And the areas of the valve ilanges 13 and 14 are so proportioned that just at, or prior to, the time of impact, the increasingrk pressure on the flange 1li will overcome the decreasing pressure on the flange 13, and the front valve section 12 will be moved forward-away from the rear section l-to the position shown in Fig. 3.

In this third position of the operating elements the communication between the reservoir 11, and the rear end of the piston chamber is shut olf-by the movement of the valve flange 13 over and beyond the equalizing ports 28-and the space behind the piston kis opened tothe atmosphere by the uncovering of the opposing ports 2,2-13-29 This permits the expanded motive fluid in the rear end of thepiston chamber to escape through the passageways 22-1829-3031 and -38; and the piston is now driven rearwardly by the expansion of the trapped fluid in the annular segregation chamber 11. The opening of the rear end of the pistonchamber to the exhaust, relieves the pressure on the front valve flange 13, [and also onthe rear valve flangel-since the air flowing through the constantly Vopen passage 32 .is carried away by the larger passages 2O-19-23l and the pressure of the trapped and expanding fluid in the space 11, andy between the flange-s 14 and 16, is thus enabled to maintain the valve elements in the position shown in Fig. 3 during the major portion of the return stroke of the piston. But when the rearwardly moving member 5 reaches and covers the exhaust ports 22, the further flow of air from the rear end of the piston chamber is stopped; and a slight additional movement of the piston also covers the Vents 23, and completely arrests the further escape of air from the back of the valve flange 1'?. The pressure of the live motive iiuid passing through the duct 32 then becomes sufficient to overcome the reduced pressure on the larger valve flange 16, and the rear valve section is thrown forward-thus restoring the parts to the position shown in Fig. 1, in which the exhaust ports 22, and the equalizing ports 28 are both closed, and the admission ports 21 are open-to admit a fresh charge of live motive fluid to the rear of the piston chamber and initiate another cycle ofoperations` rlhe action of the operative elements in the third stage of movementfMas last described-may be assisted, if desired, by the admission of a limited amount of live motive fluid through the ducts S3-(the inner ends of which are uncovered by the forward movement of the front valve section 12)-to the space between the separatedA valve flanges 14 and 16, and thence to the annular cham'- ber 11; but this auxiliary supply ci live motive fluid to the front end of the piston chamber is not essential to the effective cper ation of my improved mechanismA and'may be omitted.

In the second embodiment of my invention, which is shown in Figs. 4, 5 and 6, thegeneral construction and arrangement of the members 1, 2, 3, 4, 5 and 6'are substantially the same as is `illustrated in Figs. 1, 2

that leads. from the ports 24"L to the front of the annular chamber a, between the inner tube 4 andthe two-part valve box 8pt-'9% The front end oi the section 9 engages closely with the rear end of the casing 40,

and is thus Vheld in concentric relation with the inner tube 4; and the ktwo interengaged sections Sl-Qa are clamped in position between thecoinpressible washers and 35" and the adjacent faces of the assembled members 1 and 3, and are also held in fixed angular Yrelation with respect to the outer tube 1 by suitable dowelfpin connections or other equivalent means. rlhe distribution valve, which reciprocates in the annular chamber between the concentricmembers ll-Sa-QEL consists, as before, of twooverlapping but independently movable sections 12a and 15a; the first of these sections being provided with an internally turned flange 13u, and an externally disposedflange 14a, and the second section being provided with an external flange 16a and a shoulder 17 nearl its rear end. r he flange 14a is provided with a deep groove on its `periphery and is pierced with a row of ports 13a. The adjacent flange 16SPL is also grooved and provided with radial ports 42 that open into an annular recess 43, on the inner periphery of the section 15H.;

and the front end of this recess is cross confrom that portion of the chamber 25L that is `traversed by the valve flange 13a, to the reservoir 11; andv the opening` of this port can be varied, at will, by the adjustable screw plug 46, which is accessible through one of y the openings in the spring ring clip 37.r

lhe operation of thelast described mechanism 1s substantially the same as that of the construction shown in Figs. 1, 2 and 3. When the valvefmechanism is in the position shown in Fig'. 4 the live air vadmitted through the handle passage and chamber 39-7 passes into the rear end of the piston chamber through the open ports y21. .In this position of the Y valve elements the ports 42 are in registry withthe groove 27; the ports 45 and the communicating grooves 43-44 are in communication with the inner ends of the ports 18'nl as best shown in the enlarged view of Fig.

o) and the'outer ends of the last mentioned ports open into the inclined exhaust pas-V sages. 29a. The air in front of the advancing piston is thus permitted to escape through liao the ports and passages l0, 11-25-27- 42-43-45-4418298la-SOf and 38. When the advancing piston passes the ports 2li the live motive fluid behind it is admitted to the passageway al and to the chamber 25a in front of the valve flange 18, and both interengaged valve elements l2 l5 are thrown rearwardly to the position shown in F ig, 5. This valve movement simultaneously cuts olf communication betwen the chamber 1l and the outer air (by concurrently moving the ports 4:2 and 18a out of registry with the groove 27 and the exhaustI openings 29a) and opens communication between the said chamber and the rear end of the piston chamber (by uncovering the restricted equalizing duct 28a). The air which is trapped in the rear of the piston-together with a` restricted amount of live motive fluid which will flow through the passages 32-20-l9 and 23-is expended by the continued forward movement of the piston and by the throttled flow of the expanding fluid through the duct 28a into the segregating reservoir l1; but this equalizing flow is so restricted as to maintain a high r pressure in the rear of the advancing piston than is eX- erted on the front end thereof. At the end of the forward stroke, the increasing pressure in the chamber ll and the passages 27, which are now in communication with the space between the valve flanges 14#l and 1G, overcomes the effect of the diminishing pressure on the front face of the valve flange 13a, and the front section l2 of the valve member is thrown forward to the position shown in Fig. 6. This movement places the ports 1Sa in direct communication with the exhaust openings 22 of the inner tube 4 and also in registry with the diagonal passages 29, and thus permits the expanded fluid in the rear end of the piston chamber to escape. But the forward movement of the valve section 122L closes the port 28a, and the expansion.

from the rear side of the valve shoulder 17- is stopped, and the accumulated pressure of the live motive fluid which fiows in through the duct 32 overcomes the reduced pressure of the expanded air in the chamber 11 and passageways 25-27 (which acts on the front face of the flange 1G21) and the rear section 15'Ll is thrown forward. This restores the parts to the position shown in Fig. l and the previously described cycle of movements is repeated.

When the valve elements are separatedas shown in Fig. G-the grooved recess in the periphery of the valve flange 1Ga is brought in registry with the innerend of the restricted passageway 33; and the rear edge of the groove 44 is uncovered; and a small amount of live motive fluid is thus allowed to How from the handle reservoir 7 to the space between the valve fianges 149 and 16a, and thence, through the passages 27-25, to the segregation chamber 1l. This auxiliary supply of high pressure air assists in the maintenance of the valve elements in the position shown in Fig. 6, and also in the return of the piston to the rear end of itschamber; but it is not essential to the proper and effective operation of the mechanism and may be dispensed with if the areas of the various other supply passages, and the relative volumes of the piston and the segregation chambers, are properly proportioned.

lt will be readily understood that the degree of expansion of each live air chargeduring the impact stroke of the piston-may be controlled by varying the position of the control ports 2li; and that the ratio between the pressures on the two Vends of the piston at the end of the impact stroke (i. e., the presus in the piston chamber and the chammay be varied and controlled by the le equalizing throttle ports, 28 or will also be understood that the de- ,eirpansion of the segregated charge,

which is trapped in the chamber ll by the .generation of the valve elements (Figs. 3 or 6 is determined by the ratio between the volumes of the piston chamber, and the said segregation chamber 5 and that the volume of the latter may be varied to any required degree by altering the thickness of the inner tube d, or of the portion of it which is between the collar 6 and the front valve box section.

lt will also be apparent to those skilled in this art that my improved type of multiple expansion hammer can be operated with a much smaller amount of compressed air (or other motive fluid) than is necessary to run a pneumatic tool of the ordinary type in which the forward and the return strokes of the piston are effected by separate and successive charges of live motive fluid, which are admitted, and act at substantially constant pressure, during the entire length of travel of the reciprocating member. another important advantage of the inode of operation herein described is that the return stroke of the piston is more promptly initiated by the action of the segregated charge in the chamber 1l, than it can be by a charge of fresh motive fluid that is admitted at the opposite end of the hammer; and the speed of operation is thereby increased. This last feature of advantage is accentuated and amplified by the positioning of the admission ports 2l at the extreme rear end of the piston chamber, and the opening of these ports (by the actuation of the individual valve element l5 or 15a) before the piston has reached and covered them on its backward stroke. The reversal of the return movement, and the initiation of the forward stroke is thus accelerated, and a further increase in the average speed of reciprocation-(i. e., in the aggregate number of strokes per unit-of'times') is attained.

'My improved hammer construction also presents variousk features of structural ladvantage-such as the complete proteotion'of the distribution valve elements against any wear,or other =injury,'produced bythe vibration of the moving piston; the ready accessibility of all the operating parts; and the easy renewal `and replacement of the 'inner piston` guide tube-'all of which will be appreciated bythose familiarwith the practical construction 'and 'manipulation of this class of tools; and engineers and artisansfhaving such familiarity will, withthe preceding eisclosure as a guide, be able `to utilize my im- `provements---in'whole or in part as may be desired-in various other forms' of pressureactuated impact tools, such `as chipping hammers, air drills, sand rammers andthe like, which are not herein specifically illustrated.

What l claimis: i i A l. lnv combination in a fluid-'driven impact tool, a cylinder, a piston operating therein, a valve mechanism comprising 'two independently'movablesections, means foractuating one of said sections to admit motive fluid behind the 'piston and move it forwardly, means for actuating both sections conjointly for cutting ofi-'the supply of motive fluid during said forward stroke, and means for actuating the other ofsaid sections vtotrap lmotive fluid in front of the piston and move it rearwardly. l

2. In a fluid-'actuated percussion tool, the combination of a cylinder,'a piston reciprocable therein, la segregation chamber, a-distribution valve comprising two independently movable sections,'each responsive to variations in fluid pressure in the tool, means vfor actuating one of said sections to admit motive fluid behind the piston and drive it -forwardly,other means for actuating both sections conjointly vat an intermediatel point in said forward movement, and further means for actuating the other'of said valve sections at the completion of said forward movement of the piston. i

3. In a fluid-actuated lpercussiony tocht-he combination of a piston chamber, a vpiston reciprocable therein, a segregation chamber, a distribution valve mechanism cor'riprisingy a plurality of independently `movable sections, mea-ns for actuating one of these sections to admit fluid to the rear endof lthe piston chamber, Ameans for actuating the valve 'mechaynismas a whole tosimultaneously cut offfthe admission of vfluid to .the'rear end of the piston chamber and the escape of fluid from'the segregation chamber, and other means for independently moving another of said valve sections to opencthe rear end of the piston chamber to the exhaust.

l. A pneumatic hammer, including a piston, a'cylinder in whichthe piston-operates, a reservoir and a two part valve, said parts of the valve moving conj ointly to cut ofi| the delivery of fluid tolsaid cylinder and to deliver fluid to said reservoinand moving` independentlyto cut olf delivery of fluid-to said reservoir, and to deliver fluid to 'said cylinder.

5. A pneumatichammer, includingra piston chamber, a reservoir, a piston operating in the chamber, and a two part valve in which one part moves independently lto deliver' fluid to the cylinder andto close lthe exhaust ports thereof, and the other partmoves independently to open the exhaust ports of said cylinder and to close the exhaustfrom said reservoir, and moves with the vfirst mentioned part to deliver fluid to said reservoir while said first-mentioned part is moving to cut olf the `admission of fluid to said cylinder.

6. A pneumatic hammer, including a-,piston chamber, areservoir, a piston 'operating in the chamber and a'two part valvein which the ypart-s are adapted. to ymove independently in controlling the delivery of iluid to the cylinder and to cut off communication between the'cylinder and the reservoir, 'and in which they move Y'together :in concurrently cutting off the delivery of fluid to the lcylinder, and in establishing communication between the cylinder and the-reservoir.

7. ln combinationk in a fluid actuated impact tool, aca-sing, enclosing a segregation chamber'and aA cylinder having inlet and eX- haust ports locatedat the rear end thereof i and communicating a't its forward 4end with Ysaid chamber, a piston operating in said 'cylinder, `means for closing said inlet ports while said piston is moving forward rin response to pressure of fluid delivered therethrough, and means operative after Isaid first mentioned means to trap partially expanded fluid from said cylinder in said chamber and to simultaneously open saideXhaust ports.

S. In a fluid actuatedpercussion tool, the combination of a. cylinder enclosing a piston chamber anda segregation chamber, a piston operating within said piston chamber, a distributing Lvalve surrounding and concentric with said piston chamber and comprising two independently movable overlapping concentric sections, each responsive to variations of pressure within both of said chambers',and a flange on one of said Vsections subjectedto pressure from one ofsaid chambers for mov- 9. In combination ina liuid actuated tool, i

a casing enclosing a chamber, and a cylinder having inlet and exhaust por-'ts at the rear end thereof, said chamber and said cylinder being in open communication at the forward end thereof, a piston operating in said cylinder, means for closing said inlet ports While said piston is moving forward through said cylinder in response to the pressure of fluid delivered therethrough, and means operative after said first mentioned means for trapping partially expanded motive fluid in Said chamber to return said piston and for opening said exhaust ports.

10. In combination in a fluid actuated tool, a casing enclosing a chamber and a cylinder having inlet and exhaust ports formed in the rear end thereof, said cylinder and chamber being in open communication at the forward end of said cylinder, a piston operating in said cylinder, means movable in response to fluid pressure within said tool for closing said inlet ports and communication between said chamber and the atmosphere while said piston is moving in response to fluid pressure admitted through said inlet ports, and means operative after said first mentioned means for trapping partially expanded motive fluid from said cylinder in saidA chamber and for opening said exhaust ports.

11. In combination in a fluid actuated tool, a casing enclosing a chamber and a cylinder having inlet and exhaust ports at the rear end thereof and in op'en communcation with said chamber at the forward end thereof, a free piston operating within said cylinder, a valve mechanism at the rear end of said cylinder for closing said inlet ports while said piston is moving in response to fluid pressure delivered therethrouglnand for subsequently opening said exhaust ports and trapping partially expanded fluid from'said cylinder in said chamber to ret-urn said piston.

12. In combination in a fluid actuated percussion tool, a casing enclosing a. working cylinder having inlet and exhaust ports for motive fluid, and a segregation chamber communicating with the forward end of said cylinder, a free piston located within said cylinder, means responsive to variations of fluid pressure Within said tool for cutting off the delivery of motive fluid through said inlet ports before said piston reaches the end of its working stroke, and means operative after said first mentioned means to trap fluid from said cylinder in said chamber and to open said exhaust ports whereby said piston is returned to its initial position by the fluid trapped in said chamber.

13. In a percussion tool, a cylinder having inlet and exhaust ports for motive fluid, a segregation chamber communicating with the forward end of said cylinder, and having an exhaust passage, a free piston reciprocable within said cylinder, means for controlling the delivery of motive fluid to said cylinder through said inlet port, to move said piston in a forward direction, and to open the exhaust passage of said chamber, and means for trapping partially expanded motive fluid from said cylinder in said chamber and for simultaneously opening the exhaust/ports of said cylinder to permit the trapped fluid yto move said piston in a rearward direction in said cylinder.

14. In combination in a fluid impact tool, a casing enclosing a segregation chamber, and a cylinder having inlet and exhaust ports for motive fluid and havingV its forward end in continuous communication with said chamber, a free piston operating within said cylinder, means fo-r closing the inlet port of said cylinder and simultaneously shutting on communication between said chamber and the atmosphere while said piston is moving forwardly in response to the pressure of moive fluid delivered through said inlet ports,

and means operative after said first mentioned means to trap partially expanded fluid from said cylinder in said chamber and for simultaneously opening the exhaust ports of said cylinder.

15. In a fluid actuated impact tool, a casing enclosing a cylinder having inlet and exhaust ports for motive fluid, and a segregation chamber in open communication with the forward end of said cylinder and having an exhaust port, a valve mechanism responsive in operation to variations of the pressure of the motive huid within the working passages of said tool, for simultaneously opening the inlet port of said cylinder and the exhaust port of said chamber,.to drive said piston forward, means forv admitting fluid to sai l segregation chamber from said cylinder, and for subsequently trapping partially exy panded motive fluid from said cylinder in said chamber and simultaneously opening the exhaust port of said cylinder to drive the piston in the opposite direction.

16. In a fluid actuated percussion tool, the combination of a casing enclosing a cylinder having inlet and exhaust ports for motive fluid, and a segregation chamber having an exhaust port and communicating at its forward end with said cylinder, a free piston operating within said cylinder, and a valve mechanism comprising two independently movable sections, one for controlling the delivery of motive fluid through the inlet port of said cylinder and the exhaust port of said chamber and the other for controlling the delivery of motive fluid through the exhaust port of said cylinder and communication between the rearward end of said cylinder and said chamber, and both responsive in operation to variations in fluid pressure within. said casing.

In testimony whereof, I have hereunto subscribed my name this 28th day of July, 1921.

FRANK L. O. WADSWORTH.

IBG 

